in the gui .. you would use PROPOSALS ... think of an on-chain way of collecting signatures ..
basically, you need another account that "proposes" (proposal switch in the confirmation dialog) to move funds out of the multisig account.
Then the keys can be used to "approve" that proposal that is listed in the multisig account.

Hi,

Assume I created an  account with 3 active key 34% Weight each one.

If the account send asset to other account. How the 3 key owners sign this transaction?

Can it be done from the GUI?